An assessment of dust generation from ores

Dust from mining activities is produced from several unit operations and is often a serious problem to the industry, due to the influence it can have on human health and the safety record and productivity of a mine. So far, legislative parties and the industry have approached dust as an issue that needs to be controlled, only when a mining operation or process generates undesirable particulates. Nevertheless, new legislation and standards, such as the EU IPPC directive (Integrated Pollution Prevention and Control) and air quality strategies aim to drive mining companies to incorporate dust assessment planning that will be implemented through the whole life cycle of the mine. Mitigation and monitoring practices as well as health surveillance programs will need to be clearly defined. This project’s purpose is to understand how mining processes and in particular how the mechanisms inherent within common unit operations (i.e transfer processes using haulage roads or conveyor belts, the tipping, loading and stockpiling process, the screening process etc) result in the generation of dust. If the operation of unit operations could by optimized to produce less dust, then a “fit-for-purpose” strategy for dust minimisation could be developed to follow exploitation, processing and production demand. The literature on dust from mining operations identified that generation of fines/dust occurs due to the presence of the mechanisms of abrasion and impact. Based on this logic, an experimental methodology was developed, which aimed to assess how dust was generated for each different mechanism and for a variety of ores of different mineralogy. Five different ores were tested, a limestone, talc, an iron ore, a lamproite and a copper ore and the same experimental methodology was followed for each. Experimentation using the HSE-WSL tumbling mill test determined that under the effect of abrasion, ores yielded higher dustiness values during longer tumbling times, whilst parameters such as the sample mass and the particle size distribution of the feed sample could also influence the dust generation patterns. The findings of the computational modelling (discreet element modelling) and experimentation (high speed video recording) suggested that control and optimisation of operational parameters (e.g mill velocity, or tumbling time) within processes that involve abrasion, such as the use of conveyor belts, mills, and screens could minimise the potential of dust generation by this mechanism. The use of a novel impact test determined a positive relationship between the energy input and the particle size distributions of the broken particles, as well as the accumulation of fine particulates in the range of dust (<75μm). Also an increase in the bulk volume of ores resulted in larger quantities of fine particulates. These observations suggest that it is possible to reduce dust in processes that involve drop from heights and impaction (i.e transfer points in conveyor belts, tipping, loading) by adjusting the energy input and the bulk volume of ore at impact to as low a level possible. Particle size analysis of the produced dust fractions were found to be material dependent and varied considerably for the different ores. Almost all materials produced significant amounts of ultra fine particles below 10μm and 2.5μm, both under impact and abrasion, which reveals the potential adverse impacts to the environment and human health. Quantitative mineralogical analysis using the mineral liberation analyser determined that the dust fraction presents a different composition to that of the ore. Comparison of the results collected for the five different ores using the HSE-WSL mill and the impact test identified that certain materials yielded high dust levels under abrasion and low under impact. Therefore it would be expected that dust control approaches for such materials would differ according to the mechanisms of the involved process and the mineralogy of the sample. According to the findings of this study a reduction in dust produced from mining unit operations could be possible by optimising the involved processes either by altering their operating parameters (drop height during tipping, velocity of conveyor belt) or by optimising the design of processes so as to reduce abrasion or impact. New legislation such as the EU IPPC directive has already started considering such an approach as important, and newly developed Best Available Techniques documents refer to this as the primary step companies should follow to minimise dust. Additional advantages of this approach are that it can reduce cost for dust control by making use of less conventional mitigation practices, and in the long term it could also minimise the utilization of energy and water going to suppression, extraction and dust collection systems. In certain cases the proposed route could also optimise the production chain, especially where the generation of fines is undesirable (e.g iron ore processing or aggregates production)

Mapping the global flow of tungsten to identify key material efficiency and supply security opportunities

Tungsten is an economically important metal with diverse applications ranging from wear resistant cutting tools to its use in specialized steels and alloys. Concerns about its supply security have been raised by various studies in literature, mostly due to trade disputes arising from supply concentration and exports restrictions in China and its lack of viable substitutes. Although tungsten material flows have been analysed for specific regions, a global mass flow analysis of tungsten is still missing in literature and its global supply chain remains opaque for industry outsiders. The objective of this paper is to create a map of global tungsten flows to highlight and discuss key material efficiency (i.e. using less of a material to make a product or supply a service, or reducing the material entering production but ending up in waste) and supply security opportunities along tungsten‘s supply chain that could be incorporated into the planning and prioritization of future supply security strategies. The results indicate the existence of various intervention alternatives that could help to broaden the supply base and improve the overall material efficiency of the system. In particular, future policy and research and development (R&D) efforts to improve tungsten‘s material efficiency should focus on minimizing tungsten losses as fine particles during beneficiation and extraction (current global losses estimated at 10–40%), as well as on evaluating alternatives to improve recycling collection systems and technologies, which could lead to 17–45% more tungsten discards being recycled into new products.E. Petavratzi, T.J. Brown and A.G. Gunn publish with the permission of the Executive Director of the British Geological Survey. David R. Leal-Ayala and Julian M. Allwood were supported by the UK Engineering and Physical Sciences Research Council (EPSRC) through a Leadership fellowship (reference EP/G007217/1) and a research grant awarded to the UK Indemand Centre (reference EP/K011774/1). We thank Michael Dornhofer, Felix Gaul and Markus Ettl from Wolfram Bergbau und Hütten AG for their generous contributions to the paper.This is the accepted manuscript. The final version is available at http://www.sciencedirect.com/science/article/pii/S0921344915300367

Fuelling the Foundation Industries: Discovering the Hidden Value of Mineral Waste in the UK

The Foundation Industries (FIs) (chemical, cement, ceramic, glass, metal, and paper sectors) are worth GBP 52 billion to the UK economy and produce 75% of its materials and 10% of its total CO2 emissions. The UK extractive industry annually supplies millions of tonnes of mineral products used in FI manufacturing processes. It is estimated that mineral extraction results in upwards of 50 million tonnes of mineral waste every year. In 2021, the British Geological Survey embarked on a series of visits to UK mineral operations to improve the understanding of mineral waste production, composition, and its potential for use. This has enabled the sharing of data and information on poorly understood stocks and flows of waste materials between different industries and led to potential new applications for use of mineral wastes in novel polymer coatings and investment casting

Understanding the spatial variation in lithium concentration of high Andean Salars using diagnostic factors

Salars (basins of internal drainage) in the “Lithium Triangle” countries (Argentina, Bolivia, Chile) hold >50 % of the global lithium resources within lithium-rich brines. Given the imperative for lithium production to enable the energy transition and that salars by their very nature are highly variable, so a framework to both characterise their differences as well as identifying their similarities would be beneficial to understanding their provenance and potential for exploitation. In this study, data for 29 salars based on environmental factors: rainfall, evaporation as well as their physical characteristic: pan size and basin size have been used to characterise them along with those describing their setting land-use/cover and geological outcrop. These parameters have been normalised by creating a ratio of the lithium concentration divided by the factor for each salar. Cross-correlation has been used to develop relationships between these normalised factors, combined with principal component analysis to identify clustering and to further characterise groupings of behaviours. Two such relationships emerge out of this process: regional and local. Regional covers factors such as elevation, precipitation, and evaporation; local includes size of watershed, salar nucleus, land cover and geological outcrop in the watershed. However, Salar de Atacama is identified as an outlier and so the transferability of the understanding of its provenance and operation must be treated with caution. Other salars could be added to the framework as more information becomes available. The methodology presented here could help exploration by characterising salars into categories as their smaller size may not necessarily mean lower lithium mass. Further, such a framework can inform policy decisions and instruments by recognising the complexity of salars combined with the need to understand the environmental impacts of brine extraction

Development of a compact excavator mounted dust suppression system

This paper reports on the investigation of an excavator mounted dust suppression system for demolition and construction activities. Ever increasing pressure is placed on contractors to improve their environmental performance, especially dust emissions. Current methods of dust suppression have been investigated and each of the methods has also been critically analysed to determine their advantages and disadvantages. The investigation also examined the requirements of such a system and a concept system proposal was produced. A working prototype has been constructed for a mini excavator complete with a hydraulic breaker. The proposed system was rigorously tested in various configurations to determine its efficiency and effectiveness in comparison with current suppression techniques. The resulting benefits such as the reduction of water usage and cost are highlighted

Using Satellite Data to Analyse Raw Material Consumption in Hanoi, Vietnam

In this work, we provide an innovative route for analysing urban expansion and population growth and their link to the consumption of construction materials by combining satellite data with material consumption analysis within the Hanoi Province (Vietnam). Urban expansion is investigated with the use of landcover maps for the period 1975–2020 derived from satellite. During this period, artificial surfaces and agricultural areas have increased by 11.6% and 15.5%, respectively, while forests have decreased by 26.7%. We have used publicly available datasets to calculate and forecast the construction materials consumption and measure its statistical correlation with urban expansion between 2007 and 2018. Our results show that official figures for sand consumption are currently underestimated, and that by 2030, steel and sand and gravel consumption will increase even further by three and two times, respectively. Our analysis uses a new method to assess urban development and associated impacts by combining socio-economic and Earth Observation datasets. The analysis can provide evidence, underpin decision-making by authorities, policymakers, urban planners and sustainability experts, as well as support the development of informed strategies for resource consumption. It can also provide important information for identifying areas of land conservation and ecological greenways during urban planning

ORAMA project deliverable 1.2. Final analysis and recommendations for the improvement of statistical data collection methods in Europe for primary raw materials

This report brings together the outputs of Task 1.1 and 1.2 of Work Package 1 of the ORAMA project. Task 1.1 aims to produce an inventory of how minerals data are collected within Europe, via a survey of data providers, and Task 1.2 aims to review previous work from past projects, working groups and professional organisations in this subject area. Together this has built a comprehensive understanding of how minerals data are collected in Europe, what data gaps exist, what the issues are with regard to creating harmonised European datasets for minerals information and what good practice examples exist that lessons can be learnt from. The results of the survey show that countries that have a clear legal and regulatory procedure for collecting data often have the most robust systems in place. These countries often also have a strong motivation for collecting such data, such as receiving a significant income from mineral royalties as a result of state ownership of minerals, although resource management or land use planning also provide motivation for the collection of data. The results of the survey also showed there is a large variety in the way data is collected within Europe. This variety is not necessarily an issue with regard harmonisation as long as data providers ensure that they adhere to common data standards and classification systems, such as INSPIRE or UNFC when providing data for aggregation at a European level. The review of previous projects showed the breadth of work that had gone into the improvement of statistical datasets over the last few years. Especially from projects such as Minventory and Minerals4EU, which provide a clear roadmap for harmonising European minerals datasets, or the work of the EGS MREG (EuroGeoSurveys Mineral Resources Expert Group) towards the harmonisation of resource and reserve codes within Europe. A common theme of many of these recommendations is the need for common standards to be adhered to and that in some instances these specifications may need to be adapted to accommodate statistical data for mineral resources which are aggregated at a national scale